A visible light improved, magnetically separable TiO 2 nanocomposite was successfully synthesized... more A visible light improved, magnetically separable TiO 2 nanocomposite was successfully synthesized with silicon dioxide (SiO 2) as coating and supported on a permanent magnet Viz., nickel ferrite (NiFe 2O 4). Thus synthesized photocatalysts was further characterized for its crystalline phase, particle size, surface morphology, inorganic composition, adsorption-desorption hysteresis, BET surface area, pore size distribution, magnetic hysteresis, saturation magnetization, coercivity, elemental composition, chemical state, electronic state and visible light absorption spectra analysis with respective techniques. The crystallographic peak and inorganic elemental composition revealed the structure and composition of pure and nanocomposite TiO 2. The prepared titania nanocomposite resulted in lower band gap energy (2.26eV) and higher visible light absorption between 400 and 800nm than that of pure TiO 2 (2.76eV). The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffused sunlight irradiation. An almost complete degradation of 2,4-DCP was achieved with an initial concentration of 50mg/L for TiO 2 nanocomposite in 90min and 5h under bright and diffused sunlight conditions. Similarly pure TiO 2 resulted in a nearly complete degradation in 180min under bright and ≈90% in 5h under diffused conditions. Further the TiO 2 nanocomposite was recovered under a magnetic field with a mass recovery ≈95%. The nanocomposite also exhibited improved remanence, saturation magnetization and coercivity property along with good stability against magnetic property losses for reuse.
The scope of this study is to evaluate the performance of internal loop airlift bioreactor (ILALR... more The scope of this study is to evaluate the performance of internal loop airlift bioreactor (ILALR) in treating synthetic wastewater containing phenol and m-cresol, in single and multi component systems. The microbe utilized in the process was an indigenous mixed strain of Pseudomonas sp. isolated from a wastewater treatment plant. The reactor was operated at both lower and higher hydraulic retention times (HRTs) i.e., 4.1 and 8.3 h, respectively, by providing an inlet feed flow rate of 5 and 10 mL/min. Shock loading experiments were also performed up to a maximum concentration of 800 mg/L for phenol at 8.3 h HRT and 500 mg/L for m-cresol at 4.1 h HRT. The study showed complete degradation of both phenol and m-cresol, when they were degraded individually at a HRT of 8.3 h. Experiments with both phenol and m-cresol present as mixtures were performed based on the 2 2 full factorial design of experiments.
Growth profile of predominantly Pseudomonas species was studied using wastewater containing pheno... more Growth profile of predominantly Pseudomonas species was studied using wastewater containing phenol and m-cresol, as single and multi component systems in an internal loop airlift bioreactor (ILALR). The species utilized for the study was isolated from a wastewater treatment plant. The reactor was operated at both lower and higher hydraulic retention time (HRTs), 4.1 h and 8.3 h, respectively. The inlet phenol and concentration was varied between 100 and 800 mg/L with 800 mg/L as shock loading concentration for an HRT of 8.3 h. For 4.1 h HRT, the concentration was varied 100 and 500 mg/L using 500 mg/L as a shock loading concentration. The study showed complete degradation of both phenol and m-cresol, when present individually at an HRT of 8.3 h with an enriched biomass output. The specific growth rate of the culture at various phenol and m-cresol concentrations was fitted to a Monod model. The biokinetics value showed good potential of Pseudomonas species employing the internal loop air lift bioreactor in utilizing high strength phenolics containing wastewater. Culture growth profile with both phenol and m-cresol as mixtures also showed decreased lag times with complete utilization of the phenolics.
An adsorbent prepared from Citrus limetta peel was used to study its sorption potential on removi... more An adsorbent prepared from Citrus limetta peel was used to study its sorption potential on removing Brilliant Green dye. The initial dye concentration and sorbent dosages were varied between 10-100 mg/L and 0.5-5.0 g/L, respectively. The influence of parameters like pH, temperature, initial concentration, and adsorbent dosage on dye adsorption was also studied. A maximum dye removal of 95% was achieved with an initial concentration of 10 mg/L. The percentage removal was mathematically described as a function of experimental parameters and modeled through response surface methodology. The results show that the responses on adsorption of dyes were significantly affected by the synergistic effect of linear term of time and dosage and the quadratic term of temperature and time. A 2(4) full factorial design of experiments was adopted and statistical analysis was performed in the form of ANOVA and student "t" test, which gave good interpretation in terms of interaction of experimental parameters.
"An internal loop airlift bioreactor (ILALR) was developed and studied for biodegradation of phen... more "An internal loop airlift bioreactor (ILALR) was developed and studied for biodegradation of phenol and m-cresol as single and mixed substrate system using Pseudomonas sp. under repeated batch operation. The results showed that the culture was able to degrade phenol and m-cresol with a cumulative concentration of 600 mg L-1 each in 13 and 17 h respectively. A maximum of four steps was adopted in the study, with a substrate concentration of 125 mg L-1 for each step. The degradation rates of both the substrates were increased without lag in the degradation profile. The specific growth rates of the culture at various phenol and m-cresol concentrations were fit to Monod model. The biokinetic constants estimated using this model showed good potential of the Pseudomonas sp. in treating phenol and m-cresol in an ILALR under repeated batch mode.
"Enhanced ferromagnetic and visible light active titanium dioxide (TiO2) photocatalyst was synthe... more "Enhanced ferromagnetic and visible light active titanium dioxide (TiO2) photocatalyst was synthesised by depositing a hard ferromagnet strontium ferrite (SrFe12O19) onto TiO2 via an effortless hydrothermal and poly-condensation method. The catalysts were characterised by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and UV-visible light spectroscopy analysis. The prepared nanocomposite photocatalyst exhibited physically a powerful ferromagnetic property with significant stability against the loss of its magnetic property (coercivity ≈2200 G). The catalyst can be fluidised and recovered by an external magnetic field enhancing separation and mixing efficiency. Furthermore, it resulted in a reduced band gap (≈2.3 eV) which resulted in enhanced visible light absorption compared with unsupported TiO2. The photocatalytic activity was investigated by degrading a recalcitrant phenolic compound, viz., 2, 4-dichlorophenol (2,4-DCP) as model pollutant under different illuminance of daylight. Complete degradation of 2,4-DCP (50 mg/L initial concentration in 0.25 L) was achieved in 120 min (supported photocatalyst) and 180 min (unsupported TiO2) under higher illuminance of sunlight. Likewise under diffused sunlight, 100% degradation of 2,4-DCP was achieved in 240 min for the supported TiO2, while ≥90% degradation could be achieved in 300 min for the unsupported TiO2. The supported nanocomposite was recycled under a permanent magnetic field with a mass recovery of 98% and reused.
A visible light improved, magnetically separable TiO 2 nanocomposite was successfully synthesized... more A visible light improved, magnetically separable TiO 2 nanocomposite was successfully synthesized with silicon dioxide (SiO 2) as coating and supported on a permanent magnet Viz., nickel ferrite (NiFe 2O 4). Thus synthesized photocatalysts was further characterized for its crystalline phase, particle size, surface morphology, inorganic composition, adsorption-desorption hysteresis, BET surface area, pore size distribution, magnetic hysteresis, saturation magnetization, coercivity, elemental composition, chemical state, electronic state and visible light absorption spectra analysis with respective techniques. The crystallographic peak and inorganic elemental composition revealed the structure and composition of pure and nanocomposite TiO 2. The prepared titania nanocomposite resulted in lower band gap energy (2.26eV) and higher visible light absorption between 400 and 800nm than that of pure TiO 2 (2.76eV). The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffused sunlight irradiation. An almost complete degradation of 2,4-DCP was achieved with an initial concentration of 50mg/L for TiO 2 nanocomposite in 90min and 5h under bright and diffused sunlight conditions. Similarly pure TiO 2 resulted in a nearly complete degradation in 180min under bright and ≈90% in 5h under diffused conditions. Further the TiO 2 nanocomposite was recovered under a magnetic field with a mass recovery ≈95%. The nanocomposite also exhibited improved remanence, saturation magnetization and coercivity property along with good stability against magnetic property losses for reuse.
The scope of this study is to evaluate the performance of internal loop airlift bioreactor (ILALR... more The scope of this study is to evaluate the performance of internal loop airlift bioreactor (ILALR) in treating synthetic wastewater containing phenol and m-cresol, in single and multi component systems. The microbe utilized in the process was an indigenous mixed strain of Pseudomonas sp. isolated from a wastewater treatment plant. The reactor was operated at both lower and higher hydraulic retention times (HRTs) i.e., 4.1 and 8.3 h, respectively, by providing an inlet feed flow rate of 5 and 10 mL/min. Shock loading experiments were also performed up to a maximum concentration of 800 mg/L for phenol at 8.3 h HRT and 500 mg/L for m-cresol at 4.1 h HRT. The study showed complete degradation of both phenol and m-cresol, when they were degraded individually at a HRT of 8.3 h. Experiments with both phenol and m-cresol present as mixtures were performed based on the 2 2 full factorial design of experiments.
Growth profile of predominantly Pseudomonas species was studied using wastewater containing pheno... more Growth profile of predominantly Pseudomonas species was studied using wastewater containing phenol and m-cresol, as single and multi component systems in an internal loop airlift bioreactor (ILALR). The species utilized for the study was isolated from a wastewater treatment plant. The reactor was operated at both lower and higher hydraulic retention time (HRTs), 4.1 h and 8.3 h, respectively. The inlet phenol and concentration was varied between 100 and 800 mg/L with 800 mg/L as shock loading concentration for an HRT of 8.3 h. For 4.1 h HRT, the concentration was varied 100 and 500 mg/L using 500 mg/L as a shock loading concentration. The study showed complete degradation of both phenol and m-cresol, when present individually at an HRT of 8.3 h with an enriched biomass output. The specific growth rate of the culture at various phenol and m-cresol concentrations was fitted to a Monod model. The biokinetics value showed good potential of Pseudomonas species employing the internal loop air lift bioreactor in utilizing high strength phenolics containing wastewater. Culture growth profile with both phenol and m-cresol as mixtures also showed decreased lag times with complete utilization of the phenolics.
An adsorbent prepared from Citrus limetta peel was used to study its sorption potential on removi... more An adsorbent prepared from Citrus limetta peel was used to study its sorption potential on removing Brilliant Green dye. The initial dye concentration and sorbent dosages were varied between 10-100 mg/L and 0.5-5.0 g/L, respectively. The influence of parameters like pH, temperature, initial concentration, and adsorbent dosage on dye adsorption was also studied. A maximum dye removal of 95% was achieved with an initial concentration of 10 mg/L. The percentage removal was mathematically described as a function of experimental parameters and modeled through response surface methodology. The results show that the responses on adsorption of dyes were significantly affected by the synergistic effect of linear term of time and dosage and the quadratic term of temperature and time. A 2(4) full factorial design of experiments was adopted and statistical analysis was performed in the form of ANOVA and student "t" test, which gave good interpretation in terms of interaction of experimental parameters.
"An internal loop airlift bioreactor (ILALR) was developed and studied for biodegradation of phen... more "An internal loop airlift bioreactor (ILALR) was developed and studied for biodegradation of phenol and m-cresol as single and mixed substrate system using Pseudomonas sp. under repeated batch operation. The results showed that the culture was able to degrade phenol and m-cresol with a cumulative concentration of 600 mg L-1 each in 13 and 17 h respectively. A maximum of four steps was adopted in the study, with a substrate concentration of 125 mg L-1 for each step. The degradation rates of both the substrates were increased without lag in the degradation profile. The specific growth rates of the culture at various phenol and m-cresol concentrations were fit to Monod model. The biokinetic constants estimated using this model showed good potential of the Pseudomonas sp. in treating phenol and m-cresol in an ILALR under repeated batch mode.
"Enhanced ferromagnetic and visible light active titanium dioxide (TiO2) photocatalyst was synthe... more "Enhanced ferromagnetic and visible light active titanium dioxide (TiO2) photocatalyst was synthesised by depositing a hard ferromagnet strontium ferrite (SrFe12O19) onto TiO2 via an effortless hydrothermal and poly-condensation method. The catalysts were characterised by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and UV-visible light spectroscopy analysis. The prepared nanocomposite photocatalyst exhibited physically a powerful ferromagnetic property with significant stability against the loss of its magnetic property (coercivity ≈2200 G). The catalyst can be fluidised and recovered by an external magnetic field enhancing separation and mixing efficiency. Furthermore, it resulted in a reduced band gap (≈2.3 eV) which resulted in enhanced visible light absorption compared with unsupported TiO2. The photocatalytic activity was investigated by degrading a recalcitrant phenolic compound, viz., 2, 4-dichlorophenol (2,4-DCP) as model pollutant under different illuminance of daylight. Complete degradation of 2,4-DCP (50 mg/L initial concentration in 0.25 L) was achieved in 120 min (supported photocatalyst) and 180 min (unsupported TiO2) under higher illuminance of sunlight. Likewise under diffused sunlight, 100% degradation of 2,4-DCP was achieved in 240 min for the supported TiO2, while ≥90% degradation could be achieved in 300 min for the unsupported TiO2. The supported nanocomposite was recycled under a permanent magnetic field with a mass recovery of 98% and reused.
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http://www.sciencedirect.com/science/article/pii/S1385894712000095
https://www.sciencedirect.com/science/article/pii/S0960852409003125
http://link.springer.com/article/10.1007/s11814-010-0531-x
http://www.tandfonline.com/doi/pdf/10.1080/19443994.2012.720119
https://ser.cienve.org.tw/download/21_2/ser21-2_135-140.pdf
http://www.tandfonline.com/doi/abs/10.1080/17458080.2012.675087#.Ubp5O9iTX1U
http://www.sciencedirect.com/science/article/pii/S1385894712000095
https://www.sciencedirect.com/science/article/pii/S0960852409003125
http://link.springer.com/article/10.1007/s11814-010-0531-x
http://www.tandfonline.com/doi/pdf/10.1080/19443994.2012.720119
https://ser.cienve.org.tw/download/21_2/ser21-2_135-140.pdf
http://www.tandfonline.com/doi/abs/10.1080/17458080.2012.675087#.Ubp5O9iTX1U